<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Canvas 示例</title>
  <style>
    .sbcanvas {
      display: block;
      position: fixed;
      top: 0;
      z-index: -9;
    }
  </style>
</head>
<body>
  <canvas id="sbcanvas" class="sbcanvas"></canvas>
  <script src="./style.js"></script>
</body>
</html>
